Switching devices based on half-metals

Abstract

One embodiment of the present invention provides a switching device that can vary a spin-polarized current based on an input signal. The switching device comprises a first conducting region, a second conducting region, and a half-metal region interposed between the first conducting region and the second conducting region. The half-metal region comprises a material which, at the intrinsic Fermi level, has substantially zero available electronic states in a minority spin channel. Changing the voltage of the half-metal region with respect to the first conducting region moves its Fermi level with respect to the electron energy bands of the first conducting region, which changes the number of available electronic states in the majority spin channel, and in doing so, changes the majority-spin polarized current passing through the switching device.

Description

RELATED APPLICATION[0001]This application hereby claims priority under 35 U.S.C. §119 to U.S. Provisional Patent Application No. 60 / 573,069, filed on 21 May 2004, entitled “Switching devices made of half metals,” by inventors Ching Yao Fong, Meichun Qian, and Lin H. Yang.GOVERNMENT LICENSE RIGHTS[0002]This invention was made with Government support under Grant Nos. 0225007 and 9872053, awarded by the National Science Foundation. The Government has certain rights in this invention.BACKGROUND[0003]1. Field of the Invention[0004]The present invention is related to switching devices. More specifically, the present invention is related to switching devices comprising half-metals.[0005]2. Related Art[0006]Rapid miniaturization of semiconductor devices has dramatically reduced chip feature sizes. Today, manufacturing technologies can fabricate devices that are as small as hundred nanometers. Many experts believe that device dimensions are destined to enter the realm of quantum mechanics.[0...

AI Technical Summary

Benefits of technology

The present invention provides a switching device that can vary a spin-polarized current based on an input signal. The device comprises a half-metal region that has substantially zero available electronic states in a minority spin channel. Changing the voltage of the half-metal region with respect to the first conducting region moves its Fermi level with respect to the electron energy bands of the first conducting region, which changes the number of available electronic states in the majority spin channel, and in doing so, changes the majority-spin polarized current passing through the switching device. The switching device can be manufactured by depositing the first conducting region, depositing the half-metal region over the first conducting region, and depositing the second conducting region over the half-metal region. The device shows less reverse biased current as compared to the conventional p-n junction and a sawtooth characteristic for both reverse and forward majority spin polarized currents.

Problems solved by technology

Unfortunately, because of the doping, incoherence of carrier transport can create serious problems in device performance.

Furthermore, the most studied doped cubic semiconductor, Mn-doped GaAs, suffers from a low Curie temperature of 110 K. As a result, devices made of Mn-doped GaAs cannot be operated at room temperature.

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